SYNTHETIC AND CATALYTIC PROPERTY STUDIES ON SILICA SUPPORTED BIS-(ACETYLACETONATO) COBALT(Ⅱ) COMPLEXES^(**)

This paper reports mainly the preparation of silica supported acetylacetone ligands and their cobalt complexes, the characterization of their chemical structure, and the evaluation of their catalytic activity in the reaction for the preparation of ethers directly from alkanols and benzyl chloride. The results indicate that those silica supported β-diketone cobalt complexes (SACO) not only can simplify the reaction procedure of the ether preparation but also show a much higher catalytic activity in comparison with other homogeneous catalysts. In addition, SACO can be recovered and reused although their catalytic activity descend gradually as a result of the decrease in their cobalt content.

Cordierite Ceramics Prepared from Poor Quality Kaolin for Electric Heater Supports: Sintering Process, Phase Transformation, Microstructure Evolution and Properties

To efficiently utilize the kaolin, an economical way of preparing cordierite ceramic with high performance for electric heater supports was put forward. In this study, sintering process, phase transformation, microstructure evolutions were systematically studied by heating microscope, X-ray diffraction, scanning electronic microscope and thermal analysis. Properties（physical properties, electrical properties and coefficient of thermal expansion（CTE）） were tested for comprehensive performance evaluation. The results showed that the utilization of poor quality kaolin broadened the firing range of cordierite ceramic which was from 1 200 to 1 380 ℃. Microstructure becomes loose with increasing of the pore size, which had significant influence on bending strength and electrical properties. High content of K2 O in poor quality kaolin was the reason for liquid phase generation in sintering process, which further leads to microstructural changes. The cordierite ceramic sintered at 1 320 ℃ had the properties as follows： CTE of 1.98×10^（-6） ℃^（-1）（500 ℃）, bending strength of 90 MPa, apparent porosity of 15.1%, dielectric constant of 7.5（100 Hz）, and volume resistivity of 1.05×109 Ω·cm（100 Hz）. The comprehensive properties are very suitable for use as electric heater supports.

A NEW PROBE FOR IDENTIFYING PROPERTIES OF SUPPORTED METAL AND METAL OXIDE CATALYSTS

A novel molecular probe for identifying properties of supported transition metals and metal oxides catalysts was established.The catalytic mechanism of transition metals was proposed.

Effect of different supports on activity of Mn-Ce binary oxides catalysts for toluene combustion

The effects of support materials on catalytic performance were investigated in catalytic removal of toluene.And the Mn–Ce binary oxides as active components were supported on ZrO_(2),SiO_(2),γ-Al_(2)O_(3) and TiO_(2) support materials.Many techniques,including X-ray diffraction(XRD),Brunauer–Emmett–Teller method(BET),X-ray photoelectron spectroscopy(XPS),temperature-programmed reduction(TPR)and NH_(3)-temperature-programmed desorption(NH_(3)-TPD),were used to characterize physicochemical properties.Among the different catalysts,the MnCe/ZrO_(2) catalyst with the lowest specific surface area(39.7 m^(2)/g)shows the best catalytic activity.In terms of toluene conversion,the activity order is as follows:MnCe/ZrO_(2)>MnCe/TiO_(2)≈MnCe/SiO_(2)>MnCe/Al_(2)O_(3).The better performance of MnCe/ZrO_(2) should be attributed to the low-temperature reducibility,and abundant surface species(Mn^(4+)and lattice oxygen).And XPS and TPR results reveal that more surface abundant Mn and Ce elements generate good interaction in MnCe/ZrO_(2).The weak interaction between metal oxide and support also boosts the dispersion and complete reduction of MnCe oxides at low temperature.In addition,the in-situ DRIFTS results clarify that the carbonate species are main intermediates in MnCe/ZrO_(2) sample during surface reaction process.

Brief review of hydrocarbon-reforming catalysts map for hydrogen production

Hydrogen energy,the cleanest fuel,presents extensive applications in renewable energy technologies such as fuel cells.However,the transition process from carbon-based(fossil fuel)energy to desired hydrogen energy is usually hindered by inevitable scientific,technological,and economic obstacles,which mainly involves complex hydrocarbon reforming reactions.Hence,this paper provides a systematic and comprehensive analysis focusing on the hydrocarbon reforming mechanism.Accordingly,recent related studies are summarized to clarify the intrinsic difference among the reforming mechanism.Aiming to objectively assess the activated catalyst and deactivation mechanism,the rate-determining steps of reforming process have been emphasized,summarized,and analyzed.Specifically,the effect of metals and supports on individual reaction processes is discussed followed by the metalsupport interaction.Current tendency and research map could be established to promote the technology development and expansion of hydrocarbon reforming field.This review could be considered as the guideline for academics and industry designing appropriate catalysts.